Detergent feed systems



P 966 D. J. KILLMEYER 3,273,586

DETERGENT FEED SYSTEMS Filed Feb. 24, 1964 lllih'l 1 m Wm]! IIIIIIIIIIINVENTOR. OOA/AZD J. K/tLMEJ EIQ ATTOR/Vf).

United States Patent 3,273,586 DETERGENT FEED SYSTEMS Donald J.Killmeyer, Pittsburgh, Pa., assignor to Calgon Corporation, acorporation of Pennsylvania Filed Feb. 24, 1964, Ser. No. 346,852 3Claims. (Cl. 137--268) This invention relates to fixtures for detergentfeed systems of the type used to dispense deter-gent into commercialautomatic dishwashing machines. In particular it is an improvement indetergent dispensers of the type in which a container of dry detergentis connected in a water line and fed therefrom under control of aconductivity regulator.

Reference may be made to US. Patent 3,187,767 entitled Method ofDispensing Dry Detergent Into Dishwashing Machines issued June 8, 1965to George E. Sherrard, assignor to the assignee herein. It was knowngenerally prior to the aforesaid disclosure to control the concentrationof dishwashing detergent by the conductivity of the dishwater. See, forexample, US. Patents 2,593,825 and 2,687,139. Patent 3,187,767 disclosesan advance in the art which may utilize the original container ofdetergent by fitting it with inlet and outlet units and a downwardlyextending distributor tube for the incoming water. An embodiment of thisknown apparatus is shown in FIGURE 1 hereof, and a brief description ofits operation follows.

Container 1 of dry powdered detergent 2 includes a fixture 3 withprovision for distributor tube 4 terminating in at least one orifice 5near the bottom of the container. Fixture 3 has a lock nut 6 forattaching the inlet to an inlet pipe 7, which may be turned on and offby valve 8 which is operated by solenoid 9. Solenoid 9 is operated byconductivity control device 10 of a type known in the art which sensesthe concentration of detergent in dishwater 11 by means of conductivitycell 12. When the conductivity falls below the value set in theconductivity control device, valve 8 is opened and water flows intocontainer 1, dissolving at least some of the detergent and carrying itout through pipe 13 to empty into the dish- Water. When the conductivityis elevated by the detergent to the desired point, the valve is closedby the control device.

All of the above is known in the art. Difiiculties have developed withsuch systems, although they are otherwise quite convenient andadvantageous. The diificulties stem from two separate factors. First,the hot water and strongly alkaline detergent react adversely on fixture3 and the inlet and outlet therein, sometimes being made of plastic andperhaps imperfectly sealed to the lid of container 1. Second, gradualand sudden changes in pressure in the incoming lines can cause greatstress on the fixtures and container lid which can be damaging inthemselves and which, when combined with the extreme water temperaturessometimes used in commercial establishments, can be quite dangerous asWell as damaging to the detergent system. The changes in pressure mayoccur from operation of the rinse cycle of the machine as well as fromother machines, sinks, or the like.

I have invented an improvement in the container fixture and the outletline which virtually eliminates all serious consequences of temperatureand pressure extremes in the inlet line. My invention contemplates theprotrusion of outlet line 13 or an extension thereof into container 1for at least a short distance, and will be discussed further withreference to FIGURES 2 and 3.

FIG. 2 is an example of a detergent container fixture exhibiting myinvent-ion of a short tube added to protrude below the lower surface ofthe fixture. In FIG. 2, an exploded view shOWs the top 41 of thecontainer or drum of 3,273,586 Patented Sept. 20, 1966 "ice having twothreaded holes 47 and 48 into which fittings 49 and 50 .are inserted.Fittings 49 and 50 are adjusted to receive water pipes or tubing inwatertight relation. Fitting 50 is adapted to extend about one-half inchbelow the lower surface of drum 41 by means of an extension tube 51.

FIG. 3 shows the assembled fixture and the top portion of the drumduring operation of the device. Extension 20 of the outlet isillustrated as terminating exactly at the solution level in the drum.However, it is possible, by extending device 20 even further downward tohave a solution level higher than the terminus of device 20. The initialdepth of air-pocket 21 is determined primarily by the amount of air inthe drum or container originally, both above the top level of the drydetergent and between the granules. In a fully packed drum of one gallonvolume of detergent, there is generally about to cubic inches of airbetween the granules, where the detergent has the common mesh size ofabout 20. Of course, larger mesh sizes result in larger quantities ofair and. the smaller mesh size of detergent will be more closely packed.In a typical 8 /2 gallon container of detergent, there may normally beabout 500 cubic inches of free space above the detergent after it hassettled. The usual cushion of air, however, is not quite so large, mostof it being carried out the outlet. The remaining cushion of air createdin the free space is, where extension 20 is no greater than two inches,determined by the length thereof, but rarely will exceed 80-200 cubicinches because the air tends to dissolve in the detergent solution andsome is carried out because of turbulence.

The air pocket 21 completely insulates the fixture and all sealingsurfaces around it not only from the hot detergent solution but it alsoprovides a compressible cushion or absorber for shocks and pressurechanges in the line.

In a typical 8 /2 gallon detergent container about 14- 15 inches inheight, I prefer to use a tube 20 of about A" to about 2". Although alonger tube is operable, it is not desirable to use a tube whichterminates at a point which would create and maintain an air pocket 21of greater than one-sixth of the volume of the container. An air pocketgreater in volume than one-sixth of the container will tend to causeundesirable surging, e.g. the alternate compression and expansion of theair caused by the initial shock of water pressure will in turn causerapid changes in velocity and volume of detergent solution passedthrough the outlet. When the inlet valve is suddenly closed, theremaining compression of the air will cause a momentary continuation offeeding of solution which is unnecessary and uneconomical.

Where plumbing codes require a vacuum or siphon breaker, air will beintroduced into pipe 7 each time the inlet valve is turned on and off,thus tending to maintain the air pocket at the maximum volume permittedby the terminus of tube 20, even though some air will become dissolvedin the solution or otherwise dissipated. Thus, the length of tube 20effectively controls the volume of air pocket 21. Whether or not asiphon breaker is used, the terminus of tube 20 should be placed suchthat the air pocket formed above it is sufficiently large in volume toinsulate the fixtures from hot detergent solution and to providesufiicient air to form a cushion effective to protect the container sealfrom the shock of a change of pressure when water is turned on and off.In particular, I prefer to maintain the terminus of tube 20 at a pointsuch as to form, when the container is upright, an air pocket extendingdown to said terminus and occupying C9 about one-sixth to aboutone-twentieth of the volume of the container.

The above illustrations and discussion are mentioned for explanatorypurposes only and are not to be construed as limiting my invention. Itmay be otherwise variously embodied within the scope of the followingclaims.

I claim:

1. A granulated detergent package for automatic dispensing of detergentin solution comprising a rigid sealed container substantially filledwith dry granulated detergent, a water inlet fixture on said container,an outlet fixture on the top of said container including a terminus inthe interior of said container at a point on a horizontal plane suchthat when the container is upright, the volume above which plane is nogreater than about one-sixth of the total volume of the container butwhich is sufiiciently great when occupied by air to provide insulationfor said fixtures from hot detergent solution and effective protectionfor the container seal from pressure shocks.

2. In a detergent dispensing system wherein flow of Water through asealed container filled with originally dry granulated detergent iscontrolled by conductivity of a washing solution, including a rigidsealed container for automatic dispensing of detergent therefrom in thedissolved state, said container having an inlet fixture and an outletfixture, the improvement comprising an outlet tube extending asufiicient distance downward from said outlet fixture into the interiorof said container whereby when the detergent is dissolved by waterentering the inlet fixture, air present in the detergent mixture andelsewhere in the container will form an air pocket at the top of saidcontainer no greater in depth than the point of termination of saidoutlet tube and having a volume of about one-twentieth to aboutone-sixth of the total volume of the container, to insulate saidfittings from hot detergent solution and shock from changes in pressure.

3. In a dry granulated dishwashing detergent package for automaticdispensing of said detergent in the dissolved state comprising a sealedrigid container filled with dry granulated dis-hwashing detergent andhaving an inlet fixture and an outlet fixture, the improvementcomprising an outlet tube extending from said outlet fixture into theinterior of said package a suflicient distance that, when the containeris upright, an air pocket may be formed above the terminus of said tube,said air pocket being of a volume suflicient to insulate said fittingsfrom hot detergent solution and to substantially absorb the shock ofsudden pressure changes in said container.

References Cited by the Examiner UNITED STATES PATENTS 1/1965 Garrett137-268 8/1965 Farison 137-268

1. A GRANULATED DETERGENT PACKAGE FOR AUTOMATIC DISPENSING OF DETERGENTIN SOLUTION COMPRISING A RIGID SEALED CONTAINER SUBSTANTIALLY FILLEDWITH DRY GRANULATED DETERGENT, A WATER INLET FIXTURE ON SAID CONTAINER,AN OUTLET FIXTURE ON THE TOP OF SAID CONTAINER INCLUDING A TERMINUS INTHE INTERIOR OF SAID CONTAINER AT A POINT ON A HORIZONTAL PLANE SUCHTHAT WHEN THE CONTAINER IS UPRIGHT, THE VOLUME ABOVE WHICH PLANE IS NOGREATER THAN ABOUT ONE-SIXTH OF THE TOTAL VOLUME OF THE CONTAINER BUTWHICH IS SUFFICIENTLY GREAT WHEN OCCUPIED BY AIR TO PROVIDE INSULATIONFOR SAID FIXTURES FROM HOT DETERGENT SOLUTION AND EFFECTIVE PROTECTIONFOR THE CONTAINER SEAL FROM PRESSURE SHOCKS.